Process of recovering solvent from colloided nitrocellulose.



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' JPRWESS 0F COVERING SOLVENT Application filed March 7,

To all'wiwm it may concern:

Be it known that I, WILLIAM I the. United States, residin at Kenvil, county of Morris, and State of ew Jersey, have invented a new and useful Im- In the manufacture of smokeless explosive powder, the final treatment preparatory .to

drylng has for its object the elimination of all th '(ether and alcohol) except This treatment, which in volves prolonged distillation and treatment with Wa r, requires four separate operations, a prolonged period of time (about fourteen days), and a considerable amount of labor; and a certain percentage of the solvent is lost. The objects of the present invention are to substantially reduce the time the purpose for which they were originally used, to reduce the number of operations by preferably efiecting the resulthy means of a single two-ste process, and to reduce, or practically eliminate the factor of hand labor and manipulation.

The invention, in its broader aspect, comprises the displaoement, from the colloidecl guncotton or nitrocellulose, of the ether by alcohol, and the displacement of the alcohol by water, and th vents thus displaced;

P ation of a simplified apparatus which l have successfully employed to carry out the process on a restricted scale; it, however, being understood that the process is not dependent for its execution upon the employment of any particular apparatus.

The drawing is a diagrammatic view of an apparatus for carrying out the process.

FAWN

Specification of Letters Patent.

F. NAsH, a a

near, ASSIGNOR ro Patented lFelov 4L, ilil9u 191a. Serial Np. aaosra.

A tank a is provided for the reception of the colloided guncotton, or green colloid, Which may be inthe form of pellets sha ed like the finished product, but somew at arger due to their large solvent content. 6 fractionating column connected with tan a. c is a tank for the reception of alcohol and contains steam coils d. e is a fractionating column connected with tank 0. f is a tank containing steam coils g. A pip connected with tanks 0 and f, the connections being controlled by valves 2' and j. A pump it is interposed in pipe it. m is a return ipe from tank a to tank a. n is a pipe leading from fractionating column b to tank 0 and controlled by valve 0. p is a pipe connecting fractionating column e with tank 1' is a valve controlling communication between tank 0 and fractionating column e.

colloid. Tank 0 is charged with alcohol of the same strength as tat in tank a. By means of pump is, an endless oirculation'is established through tanks a and a and pipes k and m. The temperature of the circulating liquor is raised, by means of steam coils d, to a temperature between the boiling points of ether and alcohol. A temperature of degrees C. is found to be satisfactory. V

The circulating liquor extracts and vaporizes ether and some alcohol. These vatanks at and a into the fractionating column 6, wherein the alcohol is refluxed and the ether permitted to ass on through condensers and to storage. uring this operation the outlet to fractionating column 6 is closed by means of valve r.

The operation is continued until the desired proportion of ether contained in the colloid is replaced with alcohol. The valve .z' is now closed, thus cutting off the connection from tank a through and the val from the through pipe k. the pipe connection n from tank a to fraclit tion with tank a. The liquor in tank 0 is heated to boiling and fractionated. The ga condensed in the fractionating column 2 is drawn oil through pipe p to tank f, where it is mixed with water in an amount equaling the volume of alcohol which passes through the fractionating column 6 to the condensers and kept at a temperature of 5055 degrees C. The liquor flows from tank f through pipe it into tank a and thence through pipe m into tank 0. As the operation proceeds, the content of alcohol in the endless circuit is constantly diminishing until the liquor is almost wholly water.

When the material in tank a has ha enough solvent extracted to give the required residual solvent when dried, the circulation is stopped and the liquor in all three tanks is pumped into tank 0 and the remaining solvent content of the circulating llquor 1s fractionated oil.

The material is now dried in the usual wa 1X0 has been found that the time required for the extraction of the solvent is reduced, by the employment of my process, to about two days. The recovery of the solvent is practically complete and the products recovered are ready for immediate use for the purpose for which they were originally used. The process is a unitary one instead of one involving a number of separate and distinct successive operations. The labor required in the way of manipulation and oversight is reduced to a minimum.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. The process of removing from colloided nitrocellulose the excess of the ether and alcohol solvent contained therein, which comprises first displacing contained ether by means of alcohol and then displacing contained alcohol by means of water.

2. The process of removing from colloided nitrocellulose that part of the ether and alcohol contained therein which is not to remain in the finished product, which coniprises bringing the nitrocellulose in contact with alcohol maintained at a temperature above the boiling point of the ether and below the boiling point of the alcohol until the desired percentage of ether is eliminated by substitution and evaporation, then gradually expelling the alcohol with water until the excess of alcohol is eliminated by substitution, and subsequently drying.

3. The process of removing from colloided nitrocellulose the excess of alcohol and ether contained therein, which comprises displacing most of the ether with alcohol, and then flowing through the nitrocellulose a current of alcohol while gradually diluting the alcohol with water until the flowing naeasm current is mainly water and until most of the alcohol has been removed by substitution.

a. The process of removing from colloided nitrocellulose the excess of ether and alcohol contained therein, which comprises flowing a current of alcohol through the nitrocellulose while maintaining the temerature above the boiling point of the ether until the desired percentage of ether is eliminated by substitution and evaporation, and then flowing a current of water through the nitrocellulose and evaporating the alcohol until the excess of alcohol is removed substitution and evaporation.

5. The process of removing ed nitrocellulose the excess of alcohol and ether contained therein, which comprises displacing most of the ether with alcohol, and then, while maintaining an endless flow of alcohol through the nitrocellulose, gradually adding water to the alcohol while evaporating the alcohol until most of the alcohol has been removed from the nitrocellulose and the flowing current by substitution.

6. The process of removing from colloided nitrocellulose the excess of ether and alcohol contained therein, which comprises flowing a current of alcohol through thenitrocellulose while maintaining the temperature above the boiling point of the ether until the desired percentage of ether is eliminated by substitution and evaporation, and then, while maintaining the flow of alcoholthrough the nitrocellulose, gradually evaporating the alcohol and substituting water until most of the alcohol has been removed from the nitrocellulose and until the displacement of the alcohol by water in the flowing current has been practically complete.

7. The process of removing from colloided nitrocellulose the excess of ether and alcohol contained therein, which comprises flowing a current of alcohol through the nitrocellulose while maintaining the temperature above the boiling point of the ether and fractionaily distilling the evaporated ether, and alcohol until the solvent contained in the powder is mainly alcohol, and then with water displacing from the nitrocellulose most of the contained alcohol.

8. The process of removing ed nitrocellulose the excess of the ether-andalcohol solvent contained therein, which comprises immersing the nitrocellulose in alcohol and flowing the alcohol through the same in an endless circuit while maintaining a temperature above the boiling point of the ether; allowing the evaporated ether and the alcohol carried off therewith to escape from the circuit and separating them by fractionation; then, after the desired displacement from the nitrocellulose of ether with alcohol has been efl'ected, elevating the temperature of the alcohol to efiect its gradual evaporafrom colloid- I from colloid- I weenie tion end adding; water and continuing the plooess until the alcohol is substantially eliminated from the circuit and the desired displacement from the nitrocellulose of alc0- 5 Tool with water has been efi ected, condensing the evapomisecl aloohol and drying the product, whereby the removal of ihe solvent is WILLIAM N 

